In the fields of dyes, development of compounds having high fastness, in both light resistance and heat resistance, has been desired and earnest investigations have been carried out. Particularly, in the fields of dyes soluble in solvents and water, development of compounds having both light resistance and heat resistance has been desired.
As dyes superior in both light resistance and heat resistance, phthalocyanine compounds and Cr complexes of azo dyes are known. However, these phthalocyanine compounds are unsuitable for the absorption of visible light having wavelengths in the range from 400 to 500 nm and are therefore not useful for yellow or magenta dyes. Moreover, phthalocyanine compounds exhibit high light resistance due to their molecular association and therefore problems concerning storage stability occur, for example precipitation of the dyes from the dissolved state of these dyes in water or a solvent.
Also, it has been pointed out that because the Cr complexes of azo dyes contain Cr atoms, they are harmful to humans, organisms and the environment and improvement in this regard is highly desired. Also, azo dyes are useful dyes that have a high color value and can exhibit absorption at various wavelengths. However, non-metal complex dyes that satisfy both high light resistance and high heat resistance at the same time have not yet been found.
Among these azo dyes, compounds having a γ acid as a coupling component (for example, Acid Red 57) and compounds having pyrazolone (for example, Acid Yellow 29) have been known as azo dyes having relatively high light resistance. However, compounds that can satisfy heat resistance at the same time have not yet been found (see, for example, Patent documents 1 to 4).
Also, there is the problem that heat resistance and light resistance deterioration of these dyes becomes significant depending on the conditions of use. There is also the problem that one or both of the heat resistance and the light resistance deteriorate according to the kind of fiber to be dyed, or when they coexist with, for example, other dye compounds, photopolymerization initiators, polymerizable compounds and/or an oxidant/reducing agent, or when they are in an environment where ozone or singlet oxygen is generated.
Moreover, many dyes exhibiting high light resistance and heat resistance tend to be reduced in solubility in water or a solvent, giving rise to many problems in industrial utilization.
Patent document 1: Specification of P.L. Patent No. 101484
Patent document 2: Specification of D.T. Patent No. 2714204
Patent document 3: Specification of F.R. Patent No. 2303839
Patent document 4: Publication of Japanese Patent Laid-Open No. 58-152240